A traditional headshot for business or acting is meant to simply show what you look like. In a business headshot it’s often possible to convey the subject’s general personality, and with acting headshots the casting director should get a sense of the types of role the actor can play. The best portrait, on the other hand, goes deeper. It’s meant to give a small glimpse into who you really are, the person not the character; the inner life, not the daily facade we show the world.
A portrait may not even include the face, but instead focus on the hands or body. Or certain parts of the face or body might be blurred or steeped in shadow to draw the eye to what is most essential or interesting about the subject.